This is the shocking moment a police officer appears to throw a punch at a suspect who is being restrained by two other officers.

The video, taken by a passer-by, shows the officer apparently attacking the man as he was arrested in Derby city centre in July.

Senior officers have now launched an inquiry into the incident after studying the alarming footage.

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The video, taken by a passer-by in July, shows the officer apparently throwing a punch at the suspect as he was arrested and restrained in Holcombe Street, Derby. Police said an internal investigation had been launched

The footage shows the suspect being restrained by police and appears to show the officer arguing with him